'Thrifty' Metabolism Might Sabotage Weight Loss Efforts

MONDAY, May 11, 2015 (HealthDay News) -- A new study confirms what many frustrated dieters already suspect: Your metabolism might make it tougher for you to lose weight than others.

"The results corroborate the idea that some people who are obese may have to work harder to lose weight due to metabolic differences," said lead author Dr. Martin Reinhardt, a postdoctoral fellow at the Phoenix Epidemiology and Clinical Research Branch of the U.S. National Institute of Diabetes and Digestive and Kidney Diseases.

"But biology is not destiny. Balanced diet and regular physical activity over a long period can be very effective for weight loss," he added in an institute news release.

The small laboratory study included 12 obese men and women who underwent tests to assess their body's energy use in response to a day of fasting. This was followed by six weeks of reduced calorie intake.

After accounting for factors such as age, sex and race, the researchers found that participants who lost the least amount of weight during the six weeks of reducing calorie intake were those whose metabolism decreased the most during fasting.

These people have what the researchers called a "thrifty" metabolism, as opposed to the "spendthrift" metabolism in participants who lost the most weight and whose metabolism decreased the least during fasting.

"When people who are obese decrease the amount of food they eat, metabolic responses vary greatly, with a 'thrifty' metabolism possibly contributing to less weight lost," study co-author Susanne Votruba, an investigator at the Phoenix research branch, said in the news release.

"While behavioral factors such as adherence to diet affect weight loss to an extent, our study suggests we should consider a larger picture that includes individual physiology -- and that weight loss is one situation where being thrifty doesn't pay," she said.

The study was published May 11 in the journal Diabetes.

It's not known if people are born with different metabolic responses to lower calorie intake, or if they develop over time. Further research is needed to determine if these individual responses can be used to prevent weight gain, the study authors said.

"What we've learned from this study may one day enable a more personalized approach to help people who are obese achieve a healthy weight," Dr. Griffin Rodgers, director of the Institute of Diabetes and Digestive and Kidney Diseases, said in the news release.

More than one-third of American adults are obese, which puts them at increased risk for heart disease, diabetes and some types of cancer.

SOURCE: U.S. National Institute of Diabetes and Digestive and Kidney Diseases, news release, May 11, 2015